Migrate alloc to Rust 2024

Author: ehuss

library/alloc/Cargo.toml

@@ -8,7 +8,7 @@ repository = "https://github.com/rust-lang/rust.git"
 description = "The Rust core allocation and collections library"
 autotests = false
 autobenches = false
-edition = "2021"
+edition = "2024"
 
 [lib]
 test = false

tests/ui/macros/std-2024-macros.rs

@@ -1,13 +1,13 @@
 // Tests a small handful of macros in the standard library how they handle the
 // new behavior introduced in 2024 that allows `const{}` expressions.
 
+//@ check-pass
+
 fn main() {
     assert_eq!(0, const { 0 });
     assert_eq!(const { 0 }, const { 0 });
     assert_eq!(const { 0 }, 0);
 
     let _: Vec<Vec<String>> = vec![const { vec![] }];
-    //~^ ERROR: no rules expected keyword `const`
     let _: Vec<Vec<String>> = vec![const { vec![] }; 10];
-    //~^ ERROR: no rules expected keyword `const`
 }